An immature bald eagle lives at the Raptor Center of the Vermont Institute of Science in Woodstock, Vt. / Toby Talbot, AP

by Gary Stoller, USA TODAY

by Gary Stoller, USA TODAY

Wildlife experts in New Hampshire counted the state's highest one-day total of bald eagles in 30 years last month - another sign that the nation's once-decimated bald eagle population has almost fully recovered.

New Hampshire Audubon and its volunteers counted 69 bald eagles throughout the state on one day in February and 90 from Feb. 15 through March 1, according to Chris Martin, a raptor specialist for the wildlife group.

In January, the wildlife group counted 83 bald eagles in a two-week period - a big increase from counts decades ago. During two-week periods in January, 40 bald eagles were counted in 2003, 21 in 1993 and seven in 1983.

"We're excited to see that the bald eagle population in New Hampshire is continuing to approach full recovery," Martin says. "The population is probably about 80% recovered."

Nationally, most regions are seeing increasing populations of bald eagles, which were in danger of extinction 40 years ago.

The largest increases have been in the Northeast and northern states, according to Wade Eakle, an ecologist for the U.S. Army Corps of Engineers, which recently published results of a 25-year analysis of bald eagle counts from 1986 through 2010.

The bald eagle population is declining in the Southwest. Eakle says more monitoring and studies are needed to understand whether climate change or other factors are responsible.

The nation's bald eagle population, according to the U.S. Fish and Wildlife Service, was decimated decades ago by habitat destruction, illegal shooting and food-source contamination, largely from the use of DDT as a pesticide.

In 1963, only 417 nesting pairs of bald eagles remained, and in 1967, bald eagles were listed under the Endangered Species Act, the agency says.

The Environmental Protection Agency banned the use of DDT in 1972, and "it was the first step on the road to recovery for the bald eagle," the Fish and Wildlife Service says.

In June 2007, Fish and Wildlife announced that bald eagles had been removed from the list of threatened and endangered species.

More than 10,000 pairs of breeding eagles are in the lower 48 states, according to Eakle.

The bald eagle population in Alaska has been robust for decades and wasn't on the endangered list, Fish and Wildlife says.